Miniscope in vivo imaging of cumulative traumatic brain injury

项目摘要/摘要 在美国，每年有数百万人患有创伤性脑损伤(TBI)， 医疗保健和社会成本每年超过450亿美元。轻度脑外伤(MTBI)占75%以上 所有的颅脑损伤，许多人承受了不止一次。MTBI患者报告脑震荡后综合征(PCS) 症状包括睡眠障碍(失眠、白天嗜睡)、躯体症状(头晕、头痛、 视力模糊)、认知主诉(记忆、执行功能)和情绪问题(焦虑、抑郁、 易怒、去抑制)。对于许多人来说，PCS是暂时的，仍然有10%-25%的人报告说PCS症状持续存在。这个 MTBI后神秘的PCS症状表现和持续性促使对动态反应的调查 在大脑中将急性神经生理学与行为功能联系起来。调查小组在活体内提炼了 小型化显微镜(微型显微镜)评价脑血流量(CBF)和血液的成像方法 自由活动的小鼠的脑屏障(BBB)通透性。新的初步数据利用了 迷你镜头帽可诱发撞击加速(重量下降)闭合性头部损伤。推动这一提议的数据 可见荧光右旋糖苷在视野内的实质内立即积聚。优势所在 这种方法消除了长时间成像过程中的麻醉，允许无头的自然行为 约束，并锁定在基板上，以重复成像的单通道，广场，荧光。对于第一次 随着时间的推移，颅脑损伤对神经生理学(脑血流量、血脑屏障通透性、睡眠)的累积影响可以回归到 神经行为障碍。目前的提案检验了这样一种假设，即 脑血流量和血脑屏障通透性的MTBI可促进创伤后睡眠并预测神经损伤。 雄性和雌性小鼠通过颅窗和连接的底板准备进行微型望远镜成像。 在闭式头部冲击加速TBI中，底板头帽可替代头盔。在15秒的过渡时间内， 微型显微镜显示腹膜腔内右旋糖苷(40-2000 kDa)的CBF和BBB通透性。 薄壁组织。MTBI的累积影响通过每天两次、每天两次、 或者每隔一周一次。AIM 1监测不同时间间隔的mTBI的累积效应 脑血流同时伴有创伤后睡眠和亚急性行为表现。目标2量化了 右旋糖苷外渗与创伤后睡眠和亚急性神经功能障碍。神经学结果 包括焦虑(开阔视野)、空间记忆(新物体位置)和躯体感觉疼痛(机械 痛觉过敏)。每天两次的损伤可能表现为脑血流量、血脑屏障通透性和睡眠影响的时间总和， 在两次受伤之间恢复的时间更长。微型望远镜成像与成像技术的集成 闭合性颅脑损伤可以推动未来对颅脑损伤生理紊乱和临床处理的研究。

Project Summary/Abstract In the United States, millions of people sustain a traumatic brain injury (TBI) each year carrying individual, healthcare, and societal costs greater than $45 billion annually. Mild TBI (mTBI) accounts for more than 75% of all TBIs, with many individuals sustaining more than one. mTBI patients report post-concussion syndrome (PCS) symptoms that include sleep disorders (insomnia, daytime sleepiness), somatic symptoms (dizziness, headache, blurred vision), cognitive complaints (memory, executive function), and emotional problems (anxiety, depression, irritability, disinhibition). For many, PCS is transient, and still 10-25% report persistent PCS symptoms. The enigmatic PCS symptom presentation and persistence after mTBI urges investigation into dynamic responses in the brain that tie acute neurophysiology to behavioral function. The investigative team has refined in vivo imaging methods of miniaturized microscopes (miniscopes) to evaluate cerebral blood flow (CBF) and blood brain barrier (BBB) permeability in the unrestrained, behaving mouse. New preliminary data leverage the miniscope headcap to induce impact acceleration (weight drop) closed head injury. The data driving this proposal show immediate accumulation of fluorescent dextrans in the parenchyma within the field of view. The strength of this approach eliminates anesthesia during long-duration imaging, permits naturalistic behavior without head restraint, and locks into a baseplate for repeated imaging of single channel, wide-field, fluorescence. For the first time, the cumulative effects of TBI on neurophysiology (CBF, BBB permeability, sleep) can be regressed toward neurobehavioral impairments. The present proposal tests the hypothesis that the cumulative effects of mTBI on CBF and BBB permeability promote post-traumatic sleep and predict neurological impairments. Male and female mice are prepared for miniscope imaging through a cranial window and attached baseplate. The baseplate headcap substitutes for a helmet in closed-head impact acceleration TBI. With a 15 sec transition, miniscopes visualize CBF and BBB permeability with intraperitoneal dextrans (40-2000 kDa) in vasculature and parenchyma, respectively. The cumulative effects of mTBI are assessed with impacts delivered twice daily, daily, or every other day for a week. Aim 1 monitors the cumulative effects of mTBI with varying temporal spacing on CBF concurrent with post-traumatic sleep and subacute behavioral performance. Aim 2 quantifies the extent of dextran extravasation with post-traumatic sleep and subacute neurological performance. Neurological outcomes include anxiety (open field), spatial memory (novel object location), and somatosensory pain (mechanical hyperalgesia). Twice daily injuries likely show temporal summation of CBF, BBB permeability, and sleep effects, which are recovered with longer recovery times between injuries. The integration of miniscope imaging and closed head injury can propel future studies on physiological perturbations and clinical management of TBI.